Refrigeration unit

ABSTRACT

A system is disclosed for maintaining a predetermined temperature range in an enclosed location when the outside of the enclosed location is subjected to variations of temperature. The system includes a compressor, a first condenser located externally of the enclosed location, a cooling liquid tank, a second condenser located within the cooling liquid tank, a first evaporator located within the cooling liquid tank, a second evaporator located within the enclosed location and a control means to direct a flow of coolant to the first and/or the second evaporator in response to the temperature requirements in the enclosed location. There is also disclosed a method of maintaining the temperature in an enclosed location within a predetermined range when the outside of the enclosed location is subjected to periods of high temperature. This method includes compressing the coolant vapour in a refrigeration cycle, condensing the vapour to a liquid and feeding the liquid to evaporate in an enclosed location to cool that location and also feeding the liquid to evaporate in a cooling liquid tank to cool the cooling liquid tank. The temperature inside the enclosed location is sensed and a control system automatically controls the flows of liquid to the enclosed location and the cooling liquid tank in response to a variation of temperature inside the enclosed location.

Avon et a1.

[ REFRIGERATION UNIT [76] Inventors: Eric Joseph Avon, 108 16th Ave.,

' City of Two Mountains, Quebec;

Jack Jacob Rabow, ll Briardale Ave., Hampstead, Quebec, both of Canada [22] Filed: Mar. 7, 1973 [21] App]. No.: 338,955

[30] Foreign Application Priority Data Mar. 9, 1972 Canada 136745 [52] US. Cl 62/59, 62/115, 62/117, 62/201, 62/434, 62/435, 62/498, 62/513 [51] Int. Cl. F25d 3/00 [58] Field of Search 62/59, 115, 117, 201, 430, 62/434, 435, 498, 513

[56] References Cited UNITED STATES PATENTS 2,195,220 3/1940 McGrath... 62/228 X 2,227,244 12/1940 Candor 62/435 X 2,512,576 6/1950 Cross 62/59 2,515,825 7/1950 Grant 62/201 X 2,687,021 8/1954 Mattison 62/513 X 2,758,719 8/1956 Line 62/474 X 2,770,104 11/1956 Sweynor 62/513 X Primary ExaminerWilliam F. ODea Assistant ExaminerPeter D. Ferguson Attorney, Agent, or FirmLarson, Taylor & Hinds May 7,1974

[57] ABSTRACT outside of the enclosed location is subjected to variations of temperature. The system includes a compressor, a first condenser located externally of the en-' closed location, a cooling liquid tank, a second con denser located within the cooling liquid tank, a first evaporator located within the cooling liquid tank, a second evaporator located within the enclosed location and a control means to direct a flow of coolant to the first and/or the second evaporator in response to the temperature requirements in the enclosed location. There is also disclosed a method of maintaining the temperature in an enclosed location within a predetermined range when the outside of the enclosed location is subjected to periods of high temperature. This method includes compressing the coolant vapour in a refrigeration cycle, condensing the vapour to a liquid and feeding the liquid to evaporate in an enclosed location to cool that location and also feeding the liquid to evaporate in a cooling liquid tank to cool the cooling liquid tank. The temperature inside the enclosed location is sensed and a control system automatically controls the flows of liquid to the enclosed location and the cooling liquid tank in response to a variation of temperature inside the enclosed location.

9 Claims, 2 Drawing Figures PATENIEDm 1 m4 sum 1m 2 REFRIGERATION UNIT This invention relates to a refrigeration unit and particularly to an air conditioning unit for areas subjected to periods of excessive heat.

In everyday air conditioners used for conditioning buildings, rooms and the like, it is necessary to design them so that they have sufficient capacity to deal with the worst possible conditions, that is to say when the external temperature is at its highest point. The majority of the time however, an air conditioner is either not used or else is running at only a very small percentage of its full capacity.

One embodiment of such an installation is in the operation of overhead cranes in steel mills and other areas having furnaces which give off excessive heat. In I these conditions it is necessary to provide some form of cooling for the operator in the crane cab. In the past this has been done by use of a normal air conditioning unit however this is not completely satisfactory as when the crane cab is positioned above the furnace or in a position where it receives excessive heat it is necessary of the enclosed location, a cooling liquid tank, a second condenser located within the cooling liquid tank, a first evaporator located within the cooling liquid tank, a second evaporator located within the enclosed location, a control means to direct a flow of coolant to the first and/or the second evaporator in response to the temperature requirements in the enclosed location.

In drawings which illustrate embodiments of the invention; v

to have a high capacity air conditioner to cope with this condition. The majority of times however, the crane cab does not require such a high capacity air conditioner as it is not permanently positioned above the furnance but is moving up and down the runway in the mill.

It is the main object of the present invention to provide an air conditioning system which has a negative heat storage to draw on during conditions of excessive external heat. i

The present invention provides a negative heat storage, which is herein referred to as a cold sink, in an air conditioning'system. The use of the cold sink allows the capacity of an air conditioner operating in locations which have periods of excessive heat to be greatly reduced. In other words, the peaks which represent the power to the air conditioner during the periods of extreme heat may now be levelled off. The air conditioner can draw on the capacity of the cold sink during these periods of extreme heat, and then replenish the cold sink at timesother than the extreme conditions.

In accordance with this invention there is provided a method of maintaining the temperature in an enclosed location within a predetermined range when the outside of the enclosed location is subjected to periods of high temperature comprising the steps of: compressing a coolant vapor in a refrigeration cycle, condensing the coolant vapor to a coolant liquid by cooling in an air stream followed by further cooling in a cooling liquid tank, feeding a first stream of the coolant liquid to evaporate to a coolant vapor inside the enclosed location and thereby cool the enclosed location, feeding a second stream of coolant liquid to evaporate to a coolant vapor in the cooling liquid tank to thereby cool the cooling liquid tank, sensing the temperature inside the enclosed location and automatically controlling the flows of the first and second streams of coolant liquid in response to a variation of temperature inside the enclosed location such that the temperature inside the enclosed location remains within the predetermined range.

The present invention also provides a system of maintaining a predetermined temperature range in an enclosed location when the outside of the enclosed location is subjected to variations of temperature comprising: a compressor, a first condenser located externally FIG. 1 is a diagrammatic view showing one embodiment of an air conditioning unit of the present invention.

FIG. 2 is an electric circuit schematic of the air conditioning unit shown in FIG. 1.

Referring now to FIG. 1 the air conditioning unit is shown with a compressor having a discharge line 11 to an oil separator 12. A line 13 from the oil separator 12 passes to a first condenser 14 which is air cooled by a fan 15 driven by an electric motor 16. A discharge line 17from the first condenser 14 feeds to a cold sink tank 18. The tank 18 has a cooling liquid such as water or glycol up to the level 19 and is surrounded by insulation 20 to stop external heat entering the cold .sink tank 18. A cooling liquid circulating pump 21 driven by an electric motor 22 circulates the cooling liquid in the tank 18, collecting water from the bottom of the tank 18, and discharging it into the top of the tank 18. The discharge line 17 connects to a second condenser 23 in the tank 18. A line 24 from the second condenser 23 leaves the tank 18 and passes to a receiver tank 25.

The receiver tank 25 contains a coolant, preferably Freon or other suitable refrigeration coolant liquid in the receiver tank 25. The coolant is in liquid form in the tank 25, and leaves through a discharge line 26 which immediately divides into two separate branch lines 27 and 28. The first branch line 27 has a manual valve 29 followed by a solenoid valve 30 and a filter dryer 31. Following the filter dryer 31 is a liquid indicator 32 which is preferred but not'a necessary component of the present invention. The filter dryer 3] is to remove any moisture of air bubbles trapped in the coolant liquid, and the. liquid indicator 32, which s preferably a site glass indicator, is to observe that the dryer has removed all the air and moisture bubbles trapped in the system.

The first branch line 27 has an automatic expansion valve 33 immediately prior to the line entering afirst evaporator 34 located within the liquid in the cold sink tank 18. The second branch line 28 has a manual valve 35 followed by a solenoid valve 36 and a filter dryer 37.

An automatic expansion valve 38 is located in the line I 28 immediately prior to the entrance to a second evaporator 39 which is located within the environment requiring the temperature control, that is to say the enclosed location. The second evaporator 39 has a fan 40 and a fan motor 41. The second evaporator 39 is preferably of the fin and tube type, and heat is taken from the air blown through the second evaporator 39 by the fan 40. Suction lines from the first evaporator 34 in the cold sink tank 18 and the second evaporator 39 in the enclosed location meet at a connection 49 and are subsequently fed into the compressor 10.

In the electrical circuit shown in FIG. 2, the start button opens the protector relay 46 which in turn starts up the compressor motor 47. A low voltage transformer 48 provides power for the control system which has a water level indicator light 49 and a float switch 50 to indicate the level of the water in the cold sink tank on an indicator panel 51. A temperature sensing device (not shown) in the cold sink tank has a temperature indicator light 52 controlled by a first temperature controller 53. If the temperature in the tank reaches a predetermined point, the water temperature indicator light 52 comes on and and at the same time the first temperature controller 53 closes the solenoid 59 which closes the solenoid valve 36 in the second branch line 28 shown in FIG. 1. Thus the flow of coolant which normally passes to the second evaporator 39 in the enclosed location is cut off. The first evaporator 34 in the tank 18 as shown in FIG. 1 has a first evaporator indicator light 54 which is on under normal operating conditions when the first evaporator 34 in the tank 18 is not operating. However when the temperature sensing device (not shown) senses the temperature in the cold sink tank 18 has reached the predetermined point, a

' second temperature controller 55 turns off the first evaporator indicator light 54 and at the same time opens the solenoid 56 which opens the solenoid valve 30 in the first branch line 27 shown in FIG. 1. Thus the coolant flows to the first evaporator 34 in the cold sink tank 18 instead of the second evaporator 39 in the enclosed location. A remote control temperature sensing device (not shown) is provided in the enclosed location to be cooled. When the termperature becomes too hot in this location this temperature sensing device closes the contacts in an enclosed location controller 57. This turns on an enclosed location indicator light 58, and overrides the first temperature controller thus opening the solenoid 59 which opens the solenoid valve 36 in the second branch line 28 shown in FIG. 1. This allows coolant to flow to the second evaporator 39 in the enclosed location and therefore gives maximum cooling in that enclosed location. In this condition, the coolant flows to both the first evaporator 34 and the second evaporator 39. The motor 40 for the evaporator fan 41 in the enclosed location is connected by a separate switch 61 to the power source.

Another preferred embodiment includes a further temperature sensing device (not shown) in the cold sink tank 18 which operates a controller 62 to tripa protective relay 63 and turn off the motor 16 for the air cooled condenser fan 15. If the temperature in the cold sink tank 18 becomes too cold, and there is a possibility of freezing occurring in the tank, then the controller 62 shuts down the condenser fan 15. Furthermore if the unit is not operating, the controller 62 overrides the manual start switch 45, and starts up the compressor motor 47. The coolant then passes through the second condenser 23 which heats up the liquid in the cold sink tank 18.

In operation the air conditioning unit is started up by pressing the manual start button 45. The compressor motor 47 starts running and the compressor circulates a coolant through the system. As the collant leaves the compressor 10 it is in the form of a compressed vapour. It passes through the oil separator 12 and then to the air cooled first condenser 14 where the compressed vapour is condensed to a coolant liquid. The liquid and any compressed vapour remaining in the liquid passes down to the second condenser 23 located in the cold sink tank 18. This second condenser 23 only operates if the air temperature is too high for condensing the compressed gas coolant in the first condenser 14. The resultant coolant liquid from the second condenser 23 passes up the discharge line 24. into the receiver tank 25. If the liquid level in the cold sink tank 18 is below a predetermined limit, a float switch 50 in dicates that this level is low by the water level indicator light 49 on the panel 51. Under normal conditions, the water temperature indicator light 52 remains off and the temperature of the liquid in the cold sink tank 18 remains below a pre-set limit. Under these conditions the first temperature controller 43 for the water temperature indicator light 52 holds the solenoid 59 open, which allows coolant from the receiver tank 25 to pass through the solenoid valve 36 in the second branch line 28 and into the second evaporator 39 in the enclosed location. The second evaporator 39 has a fan 40 driven by a motor 41 which is operated by a switch 61 on a separate circuit from the compressor motor 47. The operation of the switch 61 is preferably by a thermostat in the enclosed location. If the enclosed location is too hot the motor 41 remains on, and when the required cooling has taken place, the motor 41 turns off.

When the temperature in the cold sink tank 18 rises above the pre-set limit, the first temperature controller 53 for the temperature indicator light 52 operates and the solenoid 59 is turned off thus stopping the flow of coolant to the second evaporator 39. At the same time as the water temperature indicator light 52 showing the temperature in the cold sink tank 18 has reached this pre-set limit comes on, the second temperature controller 55 turns off the first evaporator indicator light 54 from the receiver tank 25 through the solenoid valve 30 in the first branch line 27 to the first evaporator 34 in the cold sink tank 18. This cools the liquid in the tank 18 and the evaporated coolant vapour passes through the suction line to the compressor 10. In the cold sink tank 18 a water pump 21 driven by a motor 22 keeps the water continually circulating and thus ensures that the second condenser 23 does not heat the water in one area, and the first evaporator 34 cool the water in another area, but keeps the temperaturereasonably constant throughout the tank 18. The pump motor 22 is operated in connection with the compressor motor 47 If the temperature in the enclosed location becomes too hot a temperature sensing device (not shown) activates the enclosed location controller 57. This turns off the enclosed location indicator light 58, and opens the solenoid 59 thus allowing a flow of coolant to both the first evaporator 34 and the second evaporator 39.

A safety device which is a preferred embodiment is illustrated in the circuit diagram in FIG. 2 whereinthe fan motor 16 for the air cooled first condenser 14 is turned off should the temperature in the water tank become so low that freezing could occur. When the fan motor 16 is turned off, the second condenser 23 in the cold sink tank 18 produces a certain amount of heat to warm the cold sink tank and thus stop freezing. Another preferred embodiment includes a high-low pressure control for the compressor.

In a preferred embodiment wherein a crane cab is to be cooled for operating in conditions of intense heat at certain portions of the runway, it has been found that a hundred gallon cold sink tank is sufficient to operate under even the worst conditions. For preference this tank is filled with glycol to allow th unit to operate in both summer and winter. It has been found that under such conditions when the outside temperature reaches a high of F to 200 F, the temperature inside the cab is still maintained at 70 F for at least 30 minutes. When the crane leaves the area of intense heat the demand for cooling in the cab drops and the second evaporator 34 in the cold sink tank 18 cools the tank 18 as fast as possible. By using glycol the temperature in the tank 18 can be allowed to drop to 0 F without there beng a problem of freezing. In one such system the temperature sensing device was set at 36 F, and above this temperatue the first temperature controller 53 and the second temperature controller 55 were activated to change the coolant flow from the second evaporator 39 in the crane cab to the first evaporator 34 in the cold sink tank 18. When the air temperature in the crane cab exceeded 70 F, a temperature sensing device in the crane cab activated the enclosed location controller 57 and allowed the coolant to flow to both evaporators.

It will be apparent to those skilled in the art that although only one embodiment of the present invention has been disclosed, many variations may be made herein without departing from the scope of the present invention. For instance, if one were to have such a unit for a house where it was required to keep the temperature at a constant level throughout the day and night, and. there was a tremendous range of temperature between the day and night, this could be achieved by an air conditioning unit of the type disclosed-herein having a cold sink comprising a large tank of water or some other such coolant which would warm up during the day when it was required to remove as much heat as possible from the house but would be cooled down at night when not so much cooling was required in the house.

The embodiments of the invention in which an exclusive property or privilege is claimed are definedas follows:

l. A method of maintaining the temperature in an enclosed location within a predetermined range when the outside of the enclosed location is subjected to periods of high temperature comprising the steps of: compressing a coolant vapour in a refrigeration cycle, condensing the coolant vapour to a coolant liquid by cooling in an air stream followed by further cooling in a cooling liquid tank, fedding a first stream of the coolant liquid to evaporate to a coolant vapor inside the enclosed location and thereby cool the enclosed location, feeding a second stream of the coolant liquid to evaporate to a coolant vapour in the cooling liquid tank to thereby cool the cooling liquid tank, sensing the temperature inside the enclosed location and automatically controlling the flows of the first and second streams of coolant liquid in response to a variation of temperature inside the enclosed location in the sense to maintain the temperature inside the enclosed location within the predetermined range.

2. The method of claim 1 wherein the flows of the first and second streams of coolant liquid are controlled by sensing the temperature in the cooling liquid tank, further including the steps of turning off the flow of the second stream of coolant when the temperature in'the cooling liquid tank is below a predetermined point, turning on the flow of the second stream of coolant and turning off the flow of the first stream of coolant when the temperature in the cooling liquid tank is above the predetermined point, sensing the temperatrols, when the temperature in the enclosed location is above a pre-set point.

3. A system of maintaining a predetermined temperature range in an enclosed location when the outside of the enclosed location is subjected to variations of temperature comprising: a compressor, a first condenser in fluid commincation with said compressor-and located externally of the enclosed location, a cooling liquid tank, a second condenser in fluid commincation with said compressor and located within the cooling liquid tank, a first evaporator located within the cooling liquid tank, a second evaporator located within the enclosed location, a control means for selectively and variably directing a flow of coolant from said condensers to the first and/or the second evaporator in response to the temperature requirements in the enclosed location.

4. A system of maintaining a predetermined temperature range in an enclosed location when the outside of the enclosed location is subjected to variations of temperature, comprising; an enclosed refrigeration coolant cycle with a compressor adapted to compress a coolant vapour, a first condenser cooled by a flow of air located externally of the enclosed location adapted to condense the coolant vapour to a liquid, an insulated cooling liquid tank, a second condenser located within the cooling liquid tank, said second condenser being in line with the first condenser, a reservoir for the condensed coolant, a first branch line having a first evaporator located within the cooling liquid tank, a second branch line having a second evaporator in the enclosed location, means for controlling the flow of condensed coolant to the first and/or the second evaporator in response to requirements to maintain the enclosed location within a predetermined temperatue range, and a connector joining the first and second branch lines and passing to the compressor.

5. The system according to claim 4 wherein a circulating pump is provided to circulate liquid in the cooling liquid tank.

6. The system according to claim 4 wherein filter dryers are installed in the first and second branch lines.

7. The system according to claim 4 wherein a first temperature sensing device located in the cooling liquid tank indicates when the liquid in the tank has reached a predetermined temperature, a first means to simultaneously turn on the flow of coolant to the first evaporator and 'turn off the flow of coolant to the second evaporator when the predetermined temperature has been reached in the cooling liquid tank, a second temperature sensing device in the enclosed location indicates when the enclosed location has reached a predetermined temperature, and a second means to override the first means and turn on the flow of coolant to the'second evaporator when the predetermined temperature has been reached in the enclosed location.

8. The system according to claim 7 wherein a thrid temperature sensing device is located in the cooling liquid tank adapted to signal a controller when the temperature in the colling liquid tank approaches the freezing temperature of the cooling liquid, said controller shutting down the flow of air to the first condenser and circulating the coolant through the second condenser.

ture sensing device is pre-set at approximately F. 

1. A method of maintaining the temperature in an enclosed location within a predetermined range when the outside of the enclosed location is subjected to periods of high temperature comprising the steps of: compressing a coolant vapour in a refrigeration cycle, condensing the coolant vapour to a coolant liquid by cooling in an air stream followed by further cooling in a cooling liquid tank, fedding a first stream of the coolant liquid to evaporate to a coolant vapor inside the enclosed location and thereby cool the enclosed location, feeding a second stream of the coolant liquid to evaporate to a coolant vapour in the cooling liquid tank to thereby cool the cooling liquid tank, sensing the temperature inside the enclosed location and automatically controlling the flows of the first and second streams of coolant liquid in response to a variation of temperature inside the enclosed location in the sense to maintain the temperature inside the enclosed location within the predetermined range.
 2. The method of claim 1 wherein the flows of the first and second streams of coolant liquid are controlled by sensing the temperature in the cooling liquid tank, further including the steps of turning off the flow of the second stream of coolant when the temperature in the cooling liquid tank is below a predetermined point, turning on the flow of the second stream of coolant and turning off the flow of the first stream of coolant when the temperature in the cooling liquid tank is above the predetermined point, sensing the temperature in the enclosed location, and turning on the flow of the first stream of coolant, overriding the other controls, when the temperature in the enclosed location is above a pre-set point.
 3. A system of maintaining a predetermined temperature range in an enclosed location when the outside of the enclosed location is subjected to variations of temperature comprising: a compressor, a first condenser in fLuid commincation with said compressor and located externally of the enclosed location, a cooling liquid tank, a second condenser in fluid commincation with said compressor and located within the cooling liquid tank, a first evaporator located within the cooling liquid tank, a second evaporator located within the enclosed location, a control means for selectively and variably directing a flow of coolant from said condensers to the first and/or the second evaporator in response to the temperature requirements in the enclosed location.
 4. A system of maintaining a predetermined temperature range in an enclosed location when the outside of the enclosed location is subjected to variations of temperature, comprising; an enclosed refrigeration coolant cycle with a compressor adapted to compress a coolant vapour, a first condenser cooled by a flow of air located externally of the enclosed location adapted to condense the coolant vapour to a liquid, an insulated cooling liquid tank, a second condenser located within the cooling liquid tank, said second condenser being in line with the first condenser, a reservoir for the condensed coolant, a first branch line having a first evaporator located within the cooling liquid tank, a second branch line having a second evaporator in the enclosed location, means for controlling the flow of condensed coolant to the first and/or the second evaporator in response to requirements to maintain the enclosed location within a predetermined temperatue range, and a connector joining the first and second branch lines and passing to the compressor.
 5. The system according to claim 4 wherein a circulating pump is provided to circulate liquid in the cooling liquid tank.
 6. The system according to claim 4 wherein filter dryers are installed in the first and second branch lines.
 7. The system according to claim 4 wherein a first temperature sensing device located in the cooling liquid tank indicates when the liquid in the tank has reached a predetermined temperature, a first means to simultaneously turn on the flow of coolant to the first evaporator and turn off the flow of coolant to the second evaporator when the predetermined temperature has been reached in the cooling liquid tank, a second temperature sensing device in the enclosed location indicates when the enclosed location has reached a predetermined temperature, and a second means to override the first means and turn on the flow of coolant to the second evaporator when the predetermined temperature has been reached in the enclosed location.
 8. The system according to claim 7 wherein a thrid temperature sensing device is located in the cooling liquid tank adapted to signal a controller when the temperature in the colling liquid tank approaches the freezing temperature of the cooling liquid, said controller shutting down the flow of air to the first condenser and circulating the coolant through the second condenser.
 9. The system according to claim 7 wherein the cooling liquid tank is 100 gallons capacity and the cooling liquid is glycol, the first temperature sensing device is pre-set at approxiamtely 36* F and the second temperature sensing device is pre-set at approximately 70* F. 